Interaction of collisionless plasma streams

Problems concerning the expansion of cylindrical and spherical plasma clouds in a magnetized plasma background are solved by numerical simulation. Calculations carried out on the basis of a hybrid model show that the efficiency of the energy exchange between the cloud and the background is determined at large Alfven--Mach numbers by the magnetic-interaction parameter δ = (R/R/sub H/)2, where R is the gasdynamic stopping radius of the ions of the cloud, and R/sub H/ is the Larmor radius of the ions of the cloud, over a wide range of this parameter (δ = 0.1--5). The method by which this parameter is set is irrelevant here. The structure of the flow, on the other hand, depends on the method used to set the parameter δ. Incorporating the finite plasma conductivity results in a substantial decrease in the amplitude of the magnetic-field compression but has only a slight effect on the energy transfer from the cloud to the background. Incorporating the finite temeperature of the electron gas leads to a supplementary acceleration of the cloud ions